Improved Measurement of Neutrino Oscillation Parameters by the NOvA Experiment

We present new νμ → νe, νμ → νμ, ⊽ μ →⊽ e, and ⊽ μ → ⊽ μ oscillation measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the νe, νμ, ⊽ e, and ⊽ μ candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the θ23mixing angle, with Δm2⁄32 = (2.41± 0.07) x 10 -3 eV2 and sin2 θ23 = 0.57 +0.03⁄-0.04. The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of νe and⊽ e appearance. This includes values of the charge parity symmetry (CP) violating phase in the vicinity of δCP = π / 2 which are excluded by \u3e 3σ for the inverted mass ordering, and values around δCP = 3π/2 in the normal ordering which are disfavored at 2σ confidence